Staff working for jobcentres and other Department for Work and Pensions contractors have been given guidelines on how to deal with suicide threats from claimants as the squeeze on benefits takes hold.

A document sent to jobcentre staff in April details what it calls a "new policy for all DWP businesses to help them manage suicide and self-harm declarations from customers".

The guidelines include a "six-point plan" for staff to follow which says: "Some customers may say they intend to self-harm or kill themselves as a threat or a tactic to 'persuade', others will mean it. It is very hard to distinguish between the two … For this reason, all declarations must be taken seriously."

The internal document was sent to the Guardian by a senior jobcentre employee who has worked for the DWP for more than 20 years. It was accompanied by a letter from the source that said: "Absolutely nobody has ever seen this guidance before, leading staff to believe it has been put together ahead of the incapacity benefit and disability living allowance cuts."

The employee, who asked to remain anonymous, said: "We were a bit shocked. Are we preparing ourselves to be like the Samaritans? The fact that we've dealt with the public for so many years without such guidance has made people feel a bit fearful about what's coming."

The DWP said that the new guidelines were not related to any recent policy changes and had been in development since 2009. "This guidance is about supporting our staff and ensuring we can help our customers.

"It is right that a customer-facing organisation that serves over 20 million, including the most vulnerable in our society, has guidance such as this in place."

The team leader said the guidance had alarmed people in their team: "We've suddenly got this new aspect to our job. The bigger picture is people here are wondering how savage these cuts are going to be. And we're the frontline staff having to deal with the fallout from these changes. "

Julie Tipping, an appeals officer for Disability Solutions, represents claimants who try to overturn decisions made following work capability assessment tests that they are fit for work.

She says that in the last year, two of her clients have made "real attempts" at suicide after a decision was made that they were fit for work. Both were taken to hospital and subsequently sectioned.

"It's real and true. A lot of people think these people are crying wolf to get their money, but that's not the case. They are suffering from real problems and can't face it any more."

Tipping said the pressure on vulnerable clients was "the cumulative effect of all these welfare changes. The test is simply not fit for purpose for assessing mental health problems. That's on top of moving people on to jobseeker's allowance, and all of the conditionality and risk of sanctions that goes with that."

The Guardian revealed last month that some jobcentres were setting targets for advisers to stop people's benefits for not meeting conditions attached to their jobseeker's allowance.

A whistleblower said that the pressure on staff was leading to vulnerable claimants being targeted for sanctions. The targets have since been removed. But thousands of claimants of incapacity benefit and employment support allowance are being reassessed to see if they should be considered fit for work and moved on to jobseeker's allowance.

Another jobcentre adviser said: "People have been coming off sickness benefits and thrown onto jobseeker's allowance. It's problematic because some customers are clearly not fit to work, and they are clearly very distressed. When you sense this you feel really upset because the system is allowing them to get like this and you feel part of the processing machine."Eleanor Lisney, of Disabled People Against Cuts, said that the thought of being moved on to jobseeker's allowance was like a sword hanging over the heads of disabled groups and she feared an increase in related suicides.